• SIRON Fire Protection Valves

Relief Valve

Product Description

The Model A Relief Valve (RV) is UL Listed and FM Approved as a fire protection system pressure RV for installation in accordance with NFPA 13, NFPA 20, and FM Property Loss Prevention Data Sheets. The Model A is available factory-set at the following nominal operating pressures: 175 psi (12 bar), 185 psi (13 bar), 210 psi (14 bar), 260 psi (18 bar), or 310 psi (21 bar).


The Model A RV is intended for use to relieve excess pressure from fire protection systems due to thermal expansion and is also intended for installation downstream of pressure reducing valves. The Model A RV is UL Listed and FM Approved to operate between 95% and 105% of the nominal operating pressure. Select a RV with a nominal operating pressure up to 10 psi (0.7 bar) in excess of the maximum system pressure to avoid operation under normal system pressures.


The Model A RV must be installed in accordance with NFPA 13, NFPA 20, and FM Property Loss Prevention Data Sheets as well as the requirements of any authorities having jurisdiction. PTFE-based thread seal tape should be applied to the male pipe threads of the Model A RV; the Model A RV should then be installed in a 1/2-inch NPT or ISO 7-1 R1/2 threaded outlet or fitting on the sprinkler system. Tighten the Model A relief valve using a smooth jaw wrench applied to the flat sides of the relief valve. Recommended installation torque is 8 to 18 lb-ft (11 to 24 n-m). The 1/2-inch NPT or ISO 7-1 R1/2 outlet from the Model A relief valve should be piped to a location whe


Model A relief valve must be maintained in accordance with the requirements of NFPA 25.

Listings and Approvals

UL Listed to ANSI/UL1478A Pressure Relief Valves for Sprinkler Systems FM Approved to Approval Standard for Trim Water Pressure Relief Valves, Class No. 1359

siron fire protection valves relief valve model a

Relief Valve Model A

Specification 257

Nominal Operating Pressure:
- 175 psi (12 bar)
- 185 psi (13 bar)
- 210 psi (14 bar)
- 260 psi (18 bar)
- 310 psi (21 bar)
- 1/2” NPT
 -ISO 7-1 R1/2
- UL Listed
- FM Approved